A feasibility study being drawn up by a team of Maltese and German experts is looking into a so-called waste to water system that could offer the possibility of desalinating Malta’s water supply at a fraction of the cost of today’s electrically-powered reverse osmosis plants.
The concept involves using the high calorific value sewage sludge that will be produced by the waste water treatment plants planed for Malta and Gozo to desalinate sea water.
“The waste to water project involves using certain waste and taking the energy from the waste to produce heat. That heat is then used to desalinate sea water to produce fresh water, which is a problem for Malta,” explains Helmut Schnurer, a German waste expert. Dr Schnurer is in Malta as part of an EU-funded Maltese-German twinning project on implementing producer responsibility directives.
With today’s high price of fuel, the cost of powering Malta’s reverse osmosis plants has risen in tandem with the cost of electricity, and the costs are increasing as water consumption levels rise.
While different means of desalination are being studied, one option is to use sewage sludge collected by the three waste water treatment facilities in Malta and Gozo, sludge that is currently discharged into the sea. The sludge would be dried and its high calorific value used to produce vaporised sea water. The vapour is then condensed into desalinated water.
“I think it would be a good idea to achieve two goals at the same time: solving the waste problem and solving, to some degree, the water problem,” Dr Schnurer added.
“We are currently working out a feasibility study on what could be done about the problem, what the cost would be and what actual system could be used. We are also determining if we could be successful in getting funding for a private plant from the EU.
“If successful in Malta, I think we should have a German-Maltese partnership to develop such a solution for other islands in the Mediterranean and other parts of the world where fresh water supply is becoming an increasing problem.”
The feasibility study is expected to be concluded over the coming months, after which the Maltese authorities will decide whether to adopt the study’s conclusions.
Such a scheme would complement the waste to energy scheme underway at Maghtab and the engineered landfills at Ghallis and Taz Zwejra, which are expected to provide electricity for some 3,000 households.